This invention relates to a method and processing system of automatically determining the machining procedure for machining parts.
FIG. 5 is a block diagram outlining a conventional method for designing the procedure for machining parts which has been disclosed, for instance, by Japanese Patent Application Laid-Open No. Hei. 2-015949. In FIG. 5, reference numeral 1 designates an input section of parts for inputting part configurations. The term "parts configuration" as used herein is intended to mean data relating to the configuration and precision of parts to be machined including drawing data and machining operation data. Further, reference numeral 2 designates a production data base section including data relating to machine tools, cutting tools, special machining operations, etc.; reference numeral 3 designates an application section for designing a machining procedure which, in accordance with the parts configuration and the production data base, determines a machining procedure plan; 3-3, a machine selecting section for determining a machine tool to be used from both the rough configuration of parts to be machined and the data base of machine tools selected; 3-5, a reference surface determining section for determining a reference surface from the parts configuration by using the knowledge of a machining reference surface; 3-7, a machining mode determining section for determining a machining mode for a region to be machined from the parts configuration given and the data base of machine tools selected; and 3-6, a machining procedure plan making and verifying section which determines a machining procedure plan in accordance with the data which have been determined through the above-described operations, and verifies the machining procedure plan.
The data of parts to be machined or parts configurations are inputted into the computer by the parts input section. The term "parts configuration" will be defined in more detail; that is, it includes part configuration data, which includes dimensional tolerances and machining technical data consisting of machining configuration elements and precision of the machine tool. A machine tool to be used is selected in accordance with the given machine tool data base and parts configuration. Next, in accordance with tolerance data specified for the parts and the precision of the machine tool thus selected, a machining mode is determined for machining a region with the specified tolerance. A machining reference surface for the table of the machine tool is determined from the parts configuration so that it is sufficiently large in area and is machined finely. A tolerance reference surface which is used as a reference for positioning the parts and a reference for centering the parts is determined, for every machining reference surface, in accordance with the machining knowledge which ensures machining precision and allows the arrangement of fixtures.
At this stage, a plurality of machining postures, i.e. orientations of the machining blank may be obtained. In this case, a plurality of machining procedure plans may be made in accordance with the results of the above-described operations. For each of the machining procedure plans, it is detected whether or not the precision specified for the parts by the parts configuration can be attained; that is, verification of the procedure plan is carried out.
The conventional method of designing a machining procedure has the following disadvantages. Ordinary designing procedures for machining parts are determined in accordance with the experience or know-how of a production designer. Therefore, if the production designer makes a mistake in designing the procedure, then the resultant process for machining may be flawed. In general, a machining procedure plan is determined from each machining process, the characteristics of a machine tool and fixtures to be used, the dimensional precision specified for parts to be machined, and machining know-how of the production designer. However, the conventional method is provided for designing a machining procedure for only one machine tool; that is, in the case where a plurality of machine tools are used, the conventional methods cannot determine machining processes and the order of use of the machine tools, and fixtures and blanks to be used in each of the processes.
On the other hand, the provision of a compound machine tool such as a horizontal machining center or turning center makes it possible to achieve several machining operations of a conventional machine tool continuously or in one action. However, in some working sites, the flexibility of the compound machine tool is not sufficiently utilized. Furthermore, in some working sites, in addition to a compound machine tool, a general purpose machine tool which is to be operated by the operator is provided. Hence, it is considerably difficult to design a machining procedure for a working site which has a compound machine tool with a high degree of freedom; that is, in this case, the conventional method of the designing procedure which depends on the designer's experience and know-how cannot be utilized.